Cavity filters may include a cavity resonator that is used to filter electromagnetic waves. The cavity resonator includes a cavity, which is a waveguide blocked at both ends so that electromagnetic waves trapped within the resonator reflect back and forth between the two ends with specific characteristics, including a resonant frequency, that are based on the dimensions of the cavity.
Cavity filters can be electronically tunable, e.g., via the use of microelectromechanical system (MEMS) switches. However, electronically tunable cavity filters lack wideband frequency tunability, have a very low quality factor (Q), and do not maintain uniform Q over the frequency tuning range.